1. Field of the Invention
The present invention relates to a high-frequency knife for excising a living body tissue or the like.
2. Description of Related Art
In the related art, the treatment of endoscopically excising living body tissues, such as a mucous membrane, is performed. In order to perform such excision treatment, for example, a high-frequency knife described in Japanese Patent No. 3655664 is known.
In this high-frequency knife, a stopper member is coupled to a distal end of a flexible tube. A knife for an electrode is coupled to a distal end of an operating wire inserted into the flexible tube. The knife for an electrode is constituted by a relatively thin linear wire rod formed from a conductive material. A chip (larger-diameter portion) having a larger external diameter than the external diameter of the knife for an electrode is provided at a distal end of the knife for an electrode. By providing the knife for an electrode with the chip, when the tip of the knife for an electrode is unintentionally brought into contact with a tissue, the tissue can be prevented from being damaged.
The tissue coming into contact with the knife for an electrode can be incised by applying a high-frequency voltage through the operating wire in a state where the operating wire is moved (pushed in) to a distal end side with respect to the flexible tube.
In the high-frequency knife including such a larger-diameter chip, a high-frequency knife disclosed in Japan Patent No. 4315725 is known as a high-frequency knife further including a configuration in which the bleeding during incision is cleansed. In the high-frequency knife, a syringe can be detached from and attached to a cock provided at a proximal end portion of the sheath. A ring-shaped insulated chip (supporting member) is coupled to a distal end of the sheath. The insulated chip is formed with a sliding hole, and a pair of liquid-supplying opening portions are arranged around the sliding hole and communicate with an internal space of the sheath.
A conductive operating wire is inserted through the inside of the sheath so as to be movable in an axial direction. A plate-shaped electrode portion (larger-diameter portion) is coupled to the distal end of the operating wire via the rod-shaped electrode portion.
The high-frequency knife configured in this way performs incision of the tissue by applying a high-frequency voltage in a state where the operating wire is pushed in with respect to the sheath to move the rod-shaped electrode portion to the distal end side and the rod-shaped electrode portion is made to protrude from the distal end of the sheath after being introduced into a body cavity through a channel of an endoscope. When there is bleeding from an incision part in the middle of incision, a physiological salt solution (fluid) is injected into the internal space of the sheath from the syringe attached to the cock in a state where the rod-shaped electrode portion is made to protrude. As a result, the injected physiological salt solution can be injected forward from the liquid-supplying opening portions to cleanse a bleeding portion.
On the other hand, when the high-frequency knife is moved within a patient's body, within the channel of the endoscope, or the like, the operating wire is moved to (pulled back) a proximal end side with respect to the flexible tube, and the rod-shaped electrode portion is moved in a non-exposed state.